digital gauges/tank sender wires

[dogdoc]

After a couple of months and a few trips I have worked out most of the bugs from the repower. Currently my only problem is that I am pretty sure both gauges are reading my main tank and showing the level of that tank on both gauges. The garmin engine screen does read tank 1 and tank2 and gives fairly accurate levels of each tank when compared to sight gauge on the senders. The garmin gets all its data from the nmea backbone. I believe I have the gauges set up correctly with names of tanks, capacity, us ohms, etc... My question and concern is that the installer who I do not have much confidence in anymore told me to hook sender wires from each tank to the tank 1 and tank 2 connections on one gauge and not to connect anything to gauge 2. He said they would "talk" to each other. This is not what the installation diagram shows for these gauges and engine configuration. Dual digital gauges and dual df250 hp, single station. Any advice appreciated.
thanks

 

[SkunkBoat]

If the Garmn is showing both tanks then the wiring is correct. The garmin gets the info from N2k. The Zuke gauge puts that on the N2k. Both gauges are on the N2k network.

I think you might be confused by what you are looking at? The 2 gauges do not show separate tanks , they both show ALL tanks. Tanks are not Port/Starboard like gauges.

The "main" screen on both of the zuke gauges shows COMBINED fuel level. To see the split you have to scroll to the tank level screen where you should see tank 1 and tank 2 levels. This is the case on BOTH gauges.

 

[dogdoc]

Yup that did it, thanks. Unfortunately solving one problem led to another. The Garmin and the separate tank screen read about the same and accurately represent the readings of the sight gauges on the senders. The problem is that the combined tank readings screen shows a substantially lower amount of fuel. Using the Garmin, separate tank screen, and sender gauges all say I should be just over 1/2 combined capacity total of the tanks. The combined fuel reading screen however only shows 2 chiclets when I would think it should be at least 5 and maybe 6. Thoughts..
thanks

 

[seasick]

Yup that did it, thanks. Unfortunately solving one problem led to another. The Garmin and the separate tank screen read about the same and accurately represent the readings of the sight gauges on the senders. The problem is that the combined tank readings screen shows a substantially lower amount of fuel. Using the Garmin, separate tank screen, and sender gauges all say I should be just over 1/2 combined capacity total of the tanks. The combined fuel reading screen however only shows 2 chiclets when I would think it should be at least 5 and maybe 6. Thoughts..
thanks

 

[seasick]

I can't say what the issues is since neither you nor I know for sure if the individual senders are working correctly. Just because the sight glass seems to be working doesn't mean that the sender is electrically OK.
Secondly, I am not familiar with the Garmin combined fuel level page but I would guess that there is a need to configure the capacities of the individual tanks.

 

[SkunkBoat]

Yup that did it, thanks. Unfortunately solving one problem led to another. The Garmin and the separate tank screen read about the same and accurately represent the readings of the sight gauges on the senders. The problem is that the combined tank readings screen shows a substantially lower amount of fuel. Using the Garmin, separate tank screen, and sender gauges all say I should be just over 1/2 combined capacity total of the tanks. The combined fuel reading screen however only shows 2 chiclets when I would think it should be at least 5 and maybe 6. Thoughts..
thanks

You have "sight gauges"? What do you mean? They are like the one's in a portable tank? So they have a float arm and are not a WEMA/KUS type sensor?
If so...they suck...

Let me just say... DON"T expect extremely accurate readings from ANY typical boat fuel level sensor, but especially not float arm type sensors.

Fuel senders are Never accurate. They give you a reasonable guestimate. They are limited by the dead space at the top and bottom of the range of motion of the sensor and the fact that the tank bottom may have a V shape so the level and the volume are not linear. "Full" varies by how the boat is sitting when the fuel overflows. It can be different if you fill front tank before or after the rear tank.

I can burn 20 gallons from "FULL" and the gauges don't move.

The tank volume is a red herring... the Zuke gauges are looking at the voltage drop of the sensors vs the total voltage. It doesn't matter the volume of the tanks.
The Garmin "gauge" is displaying the same thing because it is getting it from the zuke gauge via N2k.

The Garmin CAN calculate remaining volume (in gallons) based on fuel burn that comes over N2k. You have to setup the tank volumes and you have to accurately reset the volume and the Trip when you add gas.
That reading has NOTHING to do with the fuel level senders. The fuel senders DO NOT update "Gallons remaining"

Use the fuel burn calculation. You have to RESET the zuke Trip by holding the ^ or v button for a few seconds. BE CAREFULL NOT TO DO THAT BETWEEN FILLUPS!!! Resetting the zuke Trip starts your Miles and Gallons burned from 0.
You have to do the same thing on the Garmin. You can "Fill Up All Tanks" or add partial gallons. Think it thru. If you don't do it right, your "Gallons remaining" will be wrong.

You can put Remaining Gallons and RANGE on the Navigation bar. That is way more useful than fuel gauges. But the gauges are a check against the Garmin in case you forgot to reset or accidentally reset at the wrong time.
I use the Garmin and it is accurate to about 5 gallons over 200 gallons

 

[dogdoc]

Sight gauge is simply a circular dial on the sender which has a needle and can reads from empty to full. Over the last 3 years they have shown to be fairly accurate based on tank volume, reading of the gauge and fuel put in to get to full reading. That is if it says 1/2 full, I can put in about 75 gallons and read full at the gauge. My question was that 3 of the 4 measurement readings coincided well. Garmin, Individual tank screen, and sight gauge all tell me about the same volume of gas in the tanks at any given time. The combined volume screen however reads much lower. Just wondered why. I have been monitoring trip mileage and fuel burn and resetting after each trip and keeping a log book. These were not things I could do with the old Yamaha engines. As an aside my friend just got repowered with Yamaha and needed a new sender when in the shop. The one they put in did not have a sight gauge and I wondered why. A search seemed to show they are not to prevalent now. Mine have been very useful and pretty accurate.
thanks